Internal, multi-seal plastic closure

ABSTRACT

A closure that includes a top panel and a skirt extending downwardly from a peripheral edge of the top panel is provided. The closure includes a tamper band which extends downwardly from the skirt and a multi-seal, seal portion which is located inside of the closure above the threads where the top panel is joined to the skirt. The tamper band and seal portion are configured to improve the removability of the closure from a mold.

FIELD OF THE INVENTION

The present invention relates generally to the field of plastic closures for containers. The present invention relates specifically to closures having multiple internal seals configured to improve removal of the closure from an injection or compression mold.

BACKGROUND OF THE INVENTION

This section is intended to provide a background or context to the invention that is recited in the claims. The description herein may include concepts that could be pursued, but are not necessarily ones that have been previously conceived or pursued. Therefore, unless otherwise indicated herein, what is described in this section is not prior art to the description and claims in this application and is not admitted to be prior art by inclusion in this section.

Closures are utilized to seal or close containers for a wide variety of items including food, drink, medicine, cleaning products, etc. For many applications, integrity of the closure and integrity of the seal between the closure and the container must be maintained from the time when the container is filled and sealed until the closure is removed from the container by the end user. A closure may be subject to a variety of impact events (e.g., dropping, impact with processing machinery, impact with adjacent containers and/or shipping materials, etc.) that may inadvertently breach the integrity of the seal between the closure and the seal which may result in contamination, spoilage or spillage of the contents of the container.

SUMMARY OF THE INVENTION

One embodiment of the invention relates to a single-piece, molded, plastic, closure. The closure includes a circular, closure panel having an internal surface; a cylindrical skirt extending from the top panel to a tamper band attached thereto, the skirt including a plurality of external raised ribs and an interior threaded portion engageable with respective threads on a container; and a seal portion. The seal portion includes an inclined seal ring extending from the internal surface and concentric with the skirt, a vertical seal ring extending from the internal surface between the inclined seal ring and the skirt and concentric with the skirt, and a top-edge seal ring extending from the internal surface between the inclined seal ring and the vertical seal ring, the inclined seal ring extending further than the vertical and top-edge seal rings, and vertical seal ring extending further than the top-edge seal ring. The inclined seal ring includes a first flat wall facing away from the skirt, and a first seal wall facing toward the skirt, the first seal wall including a first contact ring which creates a first seal with an associated container, the first seal wall including a first wall portion extending from the interior surface toward the first contact ring, the first flat wall extending from the internal surface at a first angle between 95 and 115 degrees, with a second angle between the first wall portion and the interior surface being less than the first angle. The vertical seal ring includes a second flat wall facing toward the skirt, and a second seal wall facing away from the skirt, the second seal wall including a second contact ring which creates a second seal with an associated container, the second seal wall including a second wall portion extending from the interior surface toward the second contact ring, the second flat wall extending from the internal surface at a third angle between 85 and 90 degrees, with a fourth angle between the second wall portion and the interior surface being greater than the third angle.

Another embodiment of the invention relates to a single-piece, molded, plastic closure. The closure includes a circular panel having an interior surface and a peripheral edge, a generally cylindrical skirt extending from a peripheral edge of the transition section such that the skirt is substantially perpendicular to the top wall, the skirt including a threaded portion on the interior thereof, a foldable tamper band extending from the cylindrical skirt, a plurality of raised ribs extending outwardly from an outer surface of the skirt and extending axially along at least a portion of the skirt, an inclined ring extending from the internal surface and concentric with the skirt, a vertical ring extending from the internal surface between the inclined ring and the skirt and concentric with the skirt, and a ridge extending from the internal surface between the inclined ring and the vertical ring. The inclined ring extends further than the vertical ring and the ridges, and the vertical ring extends further than the ridge. The inclined ring includes a first flat wall facing away from the skirt, and a first seal wall facing toward the skirt, the first seal wall including a first contact ring which creates a first seal with an associated container, the first seal wall including a first wall portion extending from the interior surface toward the first contact ring, the first flat wall extending from the internal surface at substantially 105 degrees, with a first angle between the first wall portion and the interior surface being less than 105 degrees. The vertical seal ring includes a second flat wall facing toward the skirt, and a second seal wall facing away from the skirt, the second seal wall including a second contact ring which creates a second seal with an associated container, the second seal wall including a second wall portion extending from the interior surface toward the second contact ring, the second flat wall extending from the internal surface at 88 degrees, with a second angle between the second wall portion and the interior surface being greater than 88 degrees.

Another embodiment of the invention relates to a sealed container. The sealed container includes a container having an opening surrounded by a hollow cylindrical neck having an interior cylindrical wall, an exterior cylindrical wall, a sealing surface extending therebetween, and a threaded portion on the exterior wall extending to an unthreaded portion of the exterior wall adjacent to the sealing surface. The container is closed with a one-piece, plastic closure. The container includes a circular, closure panel having an internal surface; a cylindrical skirt extending from the top panel to a tamper band attached thereto, the skirt including a plurality of external raised ribs and an interior threaded portion engageable with respective threads on a container; and a seal portion including an inclined seal ring extending from the internal surface and concentric with the skirt, a vertical seal ring extending from the internal surface between the inclined seal ring and the skirt and concentric with the skirt, and a top-edge seal ring extending from the internal surface between the inclined seal ring and the vertical seal ring, the inclined seal ring extending further than the vertical and top-edge seal rings, and vertical seal ring extending further than the top-edge seal ring. The inclined seal ring includes a first flat wall facing away from the skirt, and a first seal wall facing toward the skirt, the first seal wall including a first contact ring, the first seal wall including a first wall portion extending from the interior surface toward the first contact ring, the first flat wall and the internal surface extending from the internal surface at a first angle between 95 and 115 degrees, with a second angle between the first wall portion and the interior surface being less than the first angle. The vertical seal ring includes a second flat wall facing toward the skirt, and a second seal wall facing away from the skirt, the second seal wall including a second contact ring, the second seal wall including a second wall portion extending from the interior surface toward the second contact ring, the second flat wall extending from the internal surface at a third angle between 85 and 90 degrees, with a fourth angle between the second wall portion and the interior surface being greater than the third angle. When the container is fully engaged with the interior threaded portion of the closure, the first contact ring forms a seal with the interior cylindrical wall of the container, the second seal ring forms a seal with an edge at which the sealing surface meets the unthreaded portion of the container, and the top-edge seal ring forms a seal with the sealing surface of the container, wherein the angles recited above change when the closure is sealed to the container.

Alternative exemplary embodiments relate to other features and combinations of features as may be generally recited in the claims. Additionally, the dimensions used in the claims are approximate in that they are dimensions which would be expected from closures injection or compression molded from a mold designed to give a particular dimension. However, variables in processing, material quality, material consistency, etc. will cause expected variations in dimensions. Accordingly, it is the intent of the inventors that the dimensions recited in the claims cover a commensurate range beyond the particular numbers recited.

BRIEF DESCRIPTION OF THE DRAWINGS

This application will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements in which:

FIG. 1 is a perspective view of an embodiment of the exterior of a plastic closure;

FIG. 2 is an enlarged perspective view of the closure of FIG. 1, using line 2-2 of FIG. 1 as a boundary;

FIG. 3 is a top view of the closure of FIG. 1;

FIG. 4 is a sectional, profile view extending from centerline C-C and showing the profile of the closure along a section line extending through the center of the closure;

FIG. 5 is an enlarged view of the profile view of FIG. 4, using line 4-4 in FIG. 4 as a boundary; and

FIG. 6 is a sectional, profile view of a multi-seal, sealing interface between a closure and container.

FIGS. 1-6 are to scale. Accordingly, it is the intent of the inventors that the drawings be useable to determine angles, relative dimensions, relative radii, and ratios and percentages based upon the angles, relative dimensions and relative radii relating to the embodiment of the closure and associated container neck.

DETAILED DESCRIPTION OF VARIOUS EMBODIMENTS

Before turning to the figures, which illustrate the exemplary embodiments in detail, it should be understood that the present application is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology is for the purpose of description only and should not be regarded as limiting.

Referring to FIGS. 1-3, the following description made in reference to these figures provides a description of the outside of the disclosure which is just one of a number of embodiments of the outside configuration which is useable with the sealing arrangement described in reference to the remaining figures.

Referring to FIG. 1, a closure 10 is depicted according to an exemplary embodiment. The closure 10 includes a top panel or top portion, shown as a top wall 12. As shown, the top wall 12 is generally circular and is generally planar (i.e., the outer surface of the top wall 12 is flat lying substantially in a single plane, shown as a generally horizontal plane in FIG. 1). The closure 10 includes a skirt 14 and a transition section, shown as a corner section 16. The corner section 16 extends downwardly from the outer or peripheral edge 22 of the top wall 12, and the skirt 14 extends downwardly from the lower, peripheral edge 24 of the corner section 16.

The skirt 14 includes an upper section or portion 26, and a lower section or portion 28. As shown in FIG. 1, the upper portion 26 of the skirt 14 is generally circular in cross-section and is substantially perpendicular to the plane defined by the top wall 12 (i.e., the skirt 14 is generally cylindrical). The lower portion 28 is a frustoconical section extending downwardly and outwardly from the lower edge of the upper section 26. As shown in FIG. 1, the radius of the lower, peripheral edge of the lower portion 28 is greater than the radius of the top wall 12 or of the upper portion 26 of the skirt 14.

In the embodiment shown in FIG. 1, the skirt 14 includes a plurality of raised ribs 30 extending outwardly from the outer surfaces of the skirt 14 and of the corner section 16. As shown in FIG. 1, each of the raised ribs 30 includes a first or left sidewall 32 and a second or right sidewall 34. The left sidewall 32 and the right sidewall 34 are positioned at angles relative to the outer surfaces of the skirt 14 and of the corner section 16 such that the sidewalls converge to define an outer edge 36 of each raised rib 30. In one embodiment, the outer edge 36 is curved or rounded in the circumferential direction providing a smooth feel to the ribs 30. In other embodiments, the outer edge 36 is not rounded in the circumferential directions providing a sharp or rough feel to the ribs 30. In the embodiment shown, the ribs 30 are symmetric about the radial centerlines. In various embodiments, the ribs 30 are spaced and sized to provide improved grip during twist-on/twist-off of closure 10.

The closure 10 also includes a tamper evidencing structure, shown as tamper evident band 38 in FIG. 1. The tamper evident band 38 includes a frangible connecting element 41 (shown in FIG. 4) coupling the band 38 to the skirt 14. Upon application of twisting force to the closure 10, the frangible connecting element 41 is configured to break separating the tamper evident band 38 from the closure 10. Thus, the tamper evident band 38 provides a visual indication to the user of whether the closure 10 has previously been removed from the container to which it is attached.

Referring to FIG. 2, an enlarged perspective view of the corner section 16 and the skirt 14 of the closure 10 is shown. As shown in the exemplary embodiment of FIG. 2, the corner section 16 is a rounded shoulder segment having an outwardly curved outer surface 40. The corner section 16 extends from the peripheral edge 22 of the top wall 12 to the upper end of the skirt 14 such that the skirt 14 extends from the lower, peripheral edge 24 of the corner section 16.

As shown in FIG. 2, each of the raised ribs 30 includes a first portion 42 and a second portion 44. The first portions 42 of the ribs 30 extend outwardly from an outer surface of the skirt 14 and extend axially along the height of skirt 14. The second portions 44 of the ribs 30 are located above the first portions 42 and extend outwardly from the curved outer surface 40 of the corner section 16. As shown in FIG. 2, the second portions 44 define an outwardly curved, rounded shoulder that extends from the top wall 12 to the first portions 42 of the ribs 30. In the embodiment of FIG. 2, the first portion 42 is integral with the second portion 44 of each raised rib 30 such that each rib 30 is a continuous, radially outwardly extending structure that extends from the peripheral edge 22 of the top wall 12 along the corner section 16 and the skirt 14. The second portions 44 of the ribs 30 are positioned on the corner section 16 to provide improved impact resistance by absorbing energy that may be imparted to the closure 10 by contact with an object (e.g., another container or equipment during processing or shipment) or with a surface, such as the ground or floor, if the container having the closure 10 drops or falls. In one embodiment, the second portions 44 of the ribs 30 may be configured to deform or crumple upon impact to absorb impact energy, thereby preventing or resisting damage to the closure 10 that may otherwise be caused by the impact.

As shown in FIG. 2, the first portion 42 of each rib 30 includes a lower, flared section 46 that extends radially outward and along the frustoconical surface of the lower portion 28. As shown in FIG. 2, the flared section 46 of each rib 30 is shaped such that the radius of the ribs 30 at the outer edge 36 continuously increases along the axial length of the flared section 46. In one embodiment, the closure 10 is made by an injection molding process. In this embodiment, the flared sections 46 strengthen or support the skirt 14 during axial loading of the closure 10 that may occur during removal or ejection from the injection mold.

FIG. 3 is a top view of the closure 10. As shown in FIG. 3, the raised ribs 30 are evenly spaced along the skirt 14 and the corner section 16 (i.e., the spacing between each adjacent rib 30 is the same). In the embodiment shown, the number and positioning of the ribs 30 are such that the closure 10 is essentially radially symmetric. Further, in the embodiment of FIG. 3, the closure 10 is a 43 mm closure, meaning that the closure 10 is sized to fit a container neck finish having an outer thread diameter (i.e., the diameter of the container neck measured between the outer edges of the threading) of about 43 mm. In this embodiment, the number of the ribs located on the closure 10 is 90.

As shown in FIG. 3, the closure 10 includes two locating features or pull-up marks 48. The pull-up marks 48 are located along the outer surface of the skirt 14. The pull-up marks 48 identify the position of the threading located along the inner surface of the closure 10 and provides for an indication of alignment of the closure 10 as may be needed during various processes (e.g., handling, filling of the container, capping, etc.). For example, the pull-up marks 48 act as a visible feature allowing for evaluation and inspection of closure-to-container thread interaction. As shown in FIG. 3, the ribs 30 that are positioned directly above the pull-up marks 48 do not include the lower flared section 46.

FIG. 4 is a view of a preferred closure 10 which illustrates the profile of the multi-seal area/portion 53 in the interior of the closure 10. The closure 10 includes a circular, closure panel 54 having an internal surface 56. Cylindrical skirt 14 extends from the panel 54 to a tamper band 58 attached thereto. The interior of skirt 14 includes a thread 60 for engaging a corresponding thread 61 on a container (shown in FIG. 6).

The seal portion 53 includes an inclined seal ring 62 extending from the internal surface 56 and concentric with the skirt 14. A vertical seal ring 64 extends from the internal surface 56 between the inclined seal ring 62 and the skirt 14 and is concentric with the skirt 14. A top-edge seal ring 66 extends from the internal surface 56 between the inclined seal ring 62 and the vertical seal ring 64. The inclined seal ring 62 extends further from the internal surface 56 than the vertical and top-edge seal rings 64, 66, and vertical seal ring extends further from the internal surface 56 than the top-edge seal ring 66.

The inclined seal ring 62 includes a flat wall 68 facing away from the skirt 14 and a seal wall 70 facing toward the skirt 14. The seal wall 70 includes a contact ring 72 which creates a seal with an associated container (see FIG. 6). The seal wall 70 includes a wall portion 74 extending from the interior surface toward the first contact ring 72. Wall 70 also includes a rounded portion 76 which has a preferred radius of about 0.07 inches. However, depending upon the particular material, mold, molding process, etc. the radius would be modified to accommodate such variables. In another embodiment radii of between 0.065 and 0.075 inches may be used. The contact ring 72 lies on the rounded portion 76.

The flat wall 68 extends from the internal surface 56 at a preferred angle θ₁ of about 105 degrees. However, depending upon the particular material, mold, molding process, etc. the angle θ₁ would be modified to accommodate such variables and to improve mold removal as necessary. In another embodiment angles between 95 and 115 degrees may be used. The wall portion 74 extends from the internal surface 56 at a preferred angle θ₂ that is less than angle θ₁.

The vertical seal ring 64 includes a flat wall 78 facing toward the skirt 14 and a seal wall 80 facing away from the skirt 14. The seal wall 80 includes a contact ring located on a rounded portion 82 that creates a second seal between the closure 10 and an associated container. The seal wall 80 includes a wall portion 84 extending from the interior surface 56 toward the rounded portion 82. The flat wall 78 extends from the internal surface 56 at a preferred angle θ₃ of about 88 degrees. However, depending upon the particular material, mold, molding process, etc. the angle θ₃ would be modified to accommodate such variables and to improve mold removal as necessary. In another embodiment angles between 85 and 90 degrees may be used. The wall portion 84 extends from the internal surface 56 at a preferred angle θ₄ that is greater than θ₃. Rounded portion 82 has a preferred radius of about 0.03 inches. However, depending upon the particular material, mold, molding process, etc. the radius would be modified to accommodate such variables. In another embodiment radii of between 0.025 and 0.035 inches may be used.

Referring to FIG. 5, this figure includes the dimensions (in inches), angles (in degrees) and radii (in inches) for a preferred embodiment of the closure 10 in the area of the multi-seal area 53. These dimensions, angles and radii are exemplary and would be modified within appropriate ranges to accommodate variations such as closure size, manufacturing process, mold characteristics, closure material, etc. The modifications would be considered to be within the scope of the claimed invention where they provided a closure which provided at least 3 sealing rings between the closure and container where the rings 62 and 64 incurred some deflection when the closure 10 is threaded onto a container 11 to provide contact between the two as shown in FIG. 6.

As shown in FIG. 6, the closure 10 may be coupled to a container 11. In this embodiment, the container 11 includes a neck portion 86 that is open at the top end. The neck portion 86 includes threading 61. The closure 10 is coupled to the neck portion 86 via engagement between the threading 60 of the closure 10 and the threading 61 of the container 11 to seal or close the neck portion 86. While not shown in FIG. 6, the container 11 also includes a body sidewall and an end wall at the lower end of the body sidewall such that the container 11 is capable of holding material within an interior chamber 88 of the container 11. The container 11 may be any container that is sealed by a closure, such as the closure 10, and the container 11 may be suitable for holding a variety of contents including food, drink, etc., within the chamber 88.

Referring again to FIG. 6, the operation of the multi-seal area 53 can be discussed. In particular, when closure 10 is fully engaged with container 11, a seal is formed at the first contact ring 72 between the internal wall 90 of neck portion 86 and ring 62. A second seal is formed at a sealing ring between rounded portion 82 of ring 64 and a transition 92 from a threaded wall 94 to a seal surface 96 of neck portion 86. A third seal is formed at a sealing ring between ring 66 and seal surface 96. The 3 seals are formed by the pressure created at the rings by the threading 60 of closure 10 onto container 11 which also causes at least rings 62 and 64 to deflect away from neck portion 86 during sealing. Additionally, when closure 10 closes container 11, tamper band 58 folds up under a ridge (not shown) on rounded portion 82 so that the tamper band 58 is deformed and/or damaged when closure 10 is removed from container 11. Stated differently, the closure design disclosed herein allows for a sequential opening of a container where the tamper band 58 is positioned and sized relative to the ridge to break before all of the seals between closure 10 and container 11 are broken. Additionally, closure 10 can be used with a container where less than all 3 of the seals occur when the closure 10 is fully engaged with container 11. As such, closure 10 can be used with a number of different container neck portion configurations and for a number of different applications such as hot filling processes.

In addition to providing a closure which can provide up to 3 seals with a container, the disclosed configuration of closure 10 permits for a reduced cross-section to provide a very lightweight design which permits faster molding cycles and reduces shrinkage. Depending upon the process, the disclosed closure 10 configuration can allow mold removal without air pressure, without additional tooling movement such as that required for other single-piece closures, and allows for simpler mold design and fewer moving components and shut-off surfaces. The present configuration also provides a simpler construction which allows quicker design changes to accommodate container modifications and dimensional changes.

In various embodiments, the closures discussed herein may be formed from a plastic or polymer material. In various embodiments, the closures may be formed by injection molding or by compression molding. For example, the closures may be injection molded from a polypropylene homopolymer resin. In specific embodiments, the closures may be made from a clear (e.g., translucent or transparent) polypropylene homopolymer resin, or they may be made from a clear random copolymer polypropylene. In various embodiments, the clear material of the closure is such that the engagement structure (e.g., threading 60) is visible from the outside of the closure 10 through skirt 14

In various embodiments, the closures discussed herein may be of various sizes intended to seal containers of various sizes and having various contents. In some exemplary embodiments, the closures are configured to seal containers such as metal, glass or plastic containers or bottles for holding liquids, granular materials, food, etc.

Further modifications and alternative embodiments of various aspects of the invention will be apparent to those skilled in the art in view of this description. Accordingly, this description is to be construed as illustrative only. The construction and arrangements of the closure, as shown in the various exemplary embodiments, are illustrative only. Although only a few embodiments have been described in detail in this disclosure, many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter described herein. Some elements shown as integrally formed may be constructed of multiple parts or elements, the position of elements may be reversed or otherwise varied, and the nature or number of discrete elements or positions may be altered or varied. Other substitutions, modifications, changes and omissions may also be made in the design, operating conditions and arrangement of the various exemplary embodiments without departing from the scope of the present invention. 

What is claimed is:
 1. A single-piece, molded, plastic, closure comprising: a circular, closure panel having an internal surface; a cylindrical skirt extending from the top panel to a tamper band attached thereto, the skirt including a plurality of external raised ribs and an interior threaded portion engageable with respective threads on a container; and a seal portion including an inclined seal ring extending from the internal surface and concentric with the skirt, a vertical seal ring extending from the internal surface between the inclined seal ring and the skirt and concentric with the skirt, and a top-edge seal ring extending from the internal surface between the inclined seal ring and the vertical seal ring, the inclined seal ring extending further than the vertical and top-edge seal rings, and vertical seal ring extending further than the top-edge seal ring, the inclined seal ring including a first flat wall facing away from the skirt, and a first seal wall facing toward the skirt, the first seal wall including a first contact ring which creates a first seal with an associated container, the first seal wall including a first wall portion extending from the interior surface toward the first contact ring, the first flat wall extending from the internal surface at a first angle between 95 and 115 degrees, with a second angle between the first wall portion and the interior surface being less than the first angle, the vertical seal ring including a second flat wall facing toward the skirt, and a second seal wall facing away from the skirt, the second seal wall including a second contact ring which creates a second seal with an associated container, the second seal wall including a second wall portion extending from the interior surface toward the second contact ring, the second flat wall extending from the internal surface at a third angle between 85 and 90 degrees, with a fourth angle between the second wall portion and the interior surface being greater than the third angle.
 2. The closure of claim 1, wherein the first angle is 105 degrees.
 3. The closure of claim 2, wherein the second angle is 102 degrees.
 4. The closure of claim 1, wherein the third angle is 88 degrees.
 5. The closure of claim 4, wherein the fourth angle is 110 degrees.
 6. The closure of claim 1, wherein the plurality of raised ribs are each symmetric about a radial line extending through the center of each of the plurality of raised ribs.
 7. The closure of claim 1, wherein the first seal wall includes a first rounded portion which has a first radius of between 0.065 and 0.075 inches and the first contact ring lays on the first rounded portion.
 8. The closure of claim 7, wherein the first radius is 0.07 inches.
 9. The closure of claim 1, wherein the second seal wall includes a second rounded portion which has a second radius of between 0.025 and 0.035 inches and the second contact ring lays on the second rounded portion.
 10. The closure of claim 9, wherein the second radius is 0.03 inches.
 11. A single-piece, molded, plastic closure, comprising: a circular panel having an interior surface and a peripheral edge; a generally cylindrical skirt extending from a peripheral edge of the transition section such that the skirt is substantially perpendicular to the top wall, the skirt including a threaded portion on the interior thereof; a foldable tamper band extending from the cylindrical skirt; a plurality of raised ribs extending outwardly from an outer surface of the skirt and extending axially along at least a portion of the skirt; an inclined ring extending from the internal surface and concentric with the skirt, a vertical ring extending from the internal surface between the inclined ring and the skirt and concentric with the skirt, and a ridge extending from the internal surface between the inclined ring and the vertical ring, the inclined ring extending further than the vertical ring and the ridges, and vertical ring extending further than the ridge, the inclined ring including a first flat wall facing away from the skirt, and a first seal wall facing toward the skirt, the first seal wall including a first contact ring which creates a first seal with an associated container, the first seal wall including a first wall portion extending from the interior surface toward the first contact ring, the first flat wall extending from the internal surface at substantially 105 degrees, with a first angle between the first wall portion and the interior surface being less than 105 degrees, the vertical seal ring including a second flat wall facing toward the skirt, and a second seal wall facing away from the skirt, the second seal wall including a second contact ring which creates a second seal with an associated container, the second seal wall including a second wall portion extending from the interior surface toward the second contact ring, the second flat wall extending from the internal surface at 88 degrees, with a second angle between the second wall portion and the interior surface being greater than 88 degrees.
 12. The closure of claim 11, wherein the second angle is 102 degrees.
 13. The closure of claim 12, wherein the fourth angle is 110 degrees.
 14. The closure of claim 11, wherein the first seal wall includes a first rounded portion which has a first radius of between 0.065 and 0.075 inches and the first contact ring lays on the first rounded portion.
 15. The closure of claim 14, wherein the first radius is 0.07 inches.
 16. The closure of claim 14, wherein the second seal wall includes a second rounded portion which has a second radius of between 0.025 and 0.035 inches and the second contact ring lays on the second rounded portion.
 17. A sealed container comprising: a container including an opening surrounded by a hollow cylindrical neck having an interior cylindrical wall, an exterior cylindrical wall, a sealing surface extending therebetween, and a threaded portion on the exterior wall extending to an unthreaded portion of the exterior wall adjacent to the sealing surface; and a one-piece, plastic closure including: a circular, closure panel having an internal surface; a cylindrical skirt extending from the top panel to a tamper band attached thereto, the skirt including a plurality of external raised ribs and an interior threaded portion engageable with respective threads on a container; and a seal portion including an inclined seal ring extending from the internal surface and concentric with the skirt, a vertical seal ring extending from the internal surface between the inclined seal ring and the skirt and concentric with the skirt, and a top-edge seal ring extending from the internal surface between the inclined seal ring and the vertical seal ring, the inclined seal ring extending further than the vertical and top-edge seal rings, and vertical seal ring extending further than the top-edge seal ring, the inclined seal ring including a first flat wall facing away from the skirt, and a first seal wall facing toward the skirt, the first seal wall including a first contact ring, the first seal wall including a first wall portion extending from the interior surface toward the first contact ring, the first flat wall and the internal surface extending from the internal surface at a first angle between 95 and 115 degrees, with a second angle between the first wall portion and the interior surface being less than the first angle, the vertical seal ring including a second flat wall facing toward the skirt, and a second seal wall facing away from the skirt, the second seal wall including a second contact ring, the second seal wall including a second wall portion extending from the interior surface toward the second contact ring, the second flat wall extending from the internal surface at a third angle between 85 and 90 degrees, with a fourth angle between the second wall portion and the interior surface being greater than the third angle; wherein when the container is fully engaged with the interior threaded portion of the closure, the first contact ring forms a seal with the interior cylindrical wall of the container, the second seal ring forms a seal with an edge at which the sealing surface meets the unthreaded portion of the container, and the top-edge seal ring forms a seal with the sealing surface of the container, wherein the angles recited above change when the closure is sealed to the container.
 18. The container of claim 17, wherein the first seal wall includes a first rounded portion which has a first radius of between 0.065 and 0.075 inches and the first contact ring lays on the first rounded portion.
 19. The container of claim 18, wherein the second seal wall includes a second rounded portion which has a second radius of between 0.025 and 0.035 inches and the second contact ring lays on the second rounded portion.
 20. The container of claim 19, wherein the first and second become smaller when the closure is fully engaged with the container and the third and fourth angles become larger when the closure is fully engaged with the container. 